Rheumatic manifestations of Chikungunya virus infection: Prevalence, patterns, and enthesitis.

Chikungunya virus (CHIKV) is an arthropod-borne virus transmitted by mosquitoes of the genus Aedes. CHIKV infection causes various rheumatic symptoms, including enthesitis; however, these effects are rarely investigated. The aim of this study was to describe the rheumatic manifestations in CHIKV infection, estimate the prevalence of enthesitis in CHIKV-infected patients, and determine the factors associated with CHIKV-induced enthesitis. We conducted a prospective, observational study in patients with CHIKV infection confirmed by positive RT-PCR or IgM assay from October 2019 to March 2020. Patients with pre-existing inflammatory rheumatic diseases were excluded. A rheumatologist evaluated the demographic and clinical characteristics of the patients, including the number of inflamed joints, enthesitis sites, tendinitis, and tenosynovitis. The Leeds enthesitis index (LEI) and the Maastricht ankylosing spondylitis enthesis score (MASES) were used to evaluate enthesitis sites. Factors associated with enthesitis were determined using logistic regression analysis. One hundred and sixty-four participants diagnosed with CHIKV infection were enrolled. The mean (SD) age of the patients was 48.2 (14) years. The most common pattern of rheumatic manifestations was polyarthritis with or without enthesitis. Enthesitis was observed in 63 patients (38.4%). The most common site of enthesitis was the left lateral epicondyle as assessed by LEI and the posterior superior iliac spine as assessed by MASES. Multivariate analysis indicated that the number of actively inflamed joints and Thai-HAQ score at the initial evaluation were significantly associated with the presence of enthesitis. The main rheumatic manifestations of CHIKV infection were arthritis/arthralgia, with enthesitis as a prominent extraarticular feature. CHIKV infection can cause enthesitis at peripheral and axial sites. We found that enthesitis was associated with a high number of inflamed joints and reduced physical function. These results indicate that the assessment of enthesitis should be considered when monitoring disease activity and as a treatment response parameter in CHIKV-infected patients.